INTERVAL partitioning has been introduced by Oracle as an extension of RANGE partitioning. There are few limitations like the fact that’s not supported at subpartition level and the partitioning key has to be a DATE or NUMBER but also some interesting advantages. When a table is partitioned by INTERVAL, in fact, partitions are created automatically as data is loaded into the table so we don’t have to bother creating anything in advance. We might, anyway, prefer to maintain our historical data in tables that are partitioned by RANGE. This because it’s common to keep inside the system a “rolling window” (e.g. last 90 days) of historical data meaning oldest partitions are dropped as soon as they become obsolete and with INTERVAL partitioning the last partition in the range section cannot be dropped. Moreover, in many processes it’s preferrable to have a full control of which partitions are created because data loaded into the system is not guaranteed to be “clean” and rows that don’t map to existing partitions have to be rejected.
After all these considerations, let’s have a look at what we can do to make the best out of both partitioning options (tested on 11g).
